WO2013/034661 describes a sensor for measuring current in a conductor without making contact to the conductor. A first and a second magnetic bar of the sensor are placed on opposite sides of a through hole of a PCB. The first and second magnetic bar are parallel. The conductor sticks through the through hole in the PCB. A measurement coil and an excitation coil are wound around the first magnetic bar. Similarly, a measurement coil and an excitation coil are wound around the second magnetic bar such that the measurement coil and the excitation coil are concentric. The excitation coils are fed by a supply so as to regularly saturate the corresponding magnetic bars. The coils are each formed by tracks in metallization layers of the PCB, connected by vias. The changes in the current in the conductor are determined by adding and subtracting the currents through the four coils.
When performing maintenance, the current through the conductor needs to be interrupted to remove the sensor and the conductor from each other. Other sensor for measuring current in a conductor is known from US2010/301836. It is an object of the invention to provide a sensor that at least partially solves this problem.